87 Impact of Climate Change on Growing Season and Dormant Period Characteristics for the Balkan Region M. Vujadinović 1,3 , A. Vuković 1,3 , V. Djurdjević 2,3 , Z. Ranković-Vasić 1 , Z. Atanacković 1 , B. Sivčev 1 , N. Marković 1 and N. Petrović 1 1 Faculty of Agriculture, Belgrade University, Nemanjina 6, 11080 Belgrade, Serbia 2 Institute for Meteorology, Faculty of Physics, Belgrade University, Dobracina 16, 11000 Belgrade, Serbia 3 South East European Virtual Climate Change Center (hosted by Republic Hydrometeorological Service of Serbia), Bulevaroslobodjenja 8, 11000 Belgrade, Serbia Keywords: climate model, climate projections, climate impact, bias correction, grapevine Abstract The focus of this paper is to explain a proper way of using climate model simulations in climate change impact studies. Special attention is addressed to reducing model bias, a systematic model error present in all climate integrations. Studies are done using climate projection results obtained by the Coupled Regional Climate Model EBU-POM, for three periods: 1961-1990 (experiment 20c3m), 2001- 2030 (A1B scenario) and 2071-2100 (A2 scenario) for the Balkan area with special analysis of vineyard regions in Serbia. A Statistical Bias Correction method, based on daily values, is applied to the model results in order to minimize bias. Corrected values for 2 m air temperature and precipitation are used to calculate several climate indicators important for grape growing. Obtained results show that projected increase in temperature may lead to an extended growing season duration, as well as an increase in Growing Degree-Days by 1000 units, by the end of the 21 st century. The grapevine dormant period is likely to be shortened and affected by warmer winters with less frost days. Changes in water supply and overheating could lead to changes in vineyard locations or changes in the selection of grapevine cultivars. Presented results show that the present climate conditions in vineyard regions could be shifted to higher altitudes (1000 m) by the end of the century. INTRODUCTION Favorable climate is one of the most important conditions for successful grape growing and wine production. While other grape growing factors can be modified to some degree, climate cannot making it the main indicator for cultivar selection. Many studies indicate that climate is changing at the global level and consequences could lead to an extensive change in present vineyard regions (Jones et al., 2005; Metzger et al., 2008). The IPCC Forth Assessment Report (Christensen et al., 2007) shows that Global Climate Models (GCMs) project an increase in precipitation in the northern part and a decrease in the southern part of the northern hemisphere. The region between the two areas with different trends in precipitation has different placement in GCM projections, shifted more or less on the north or south, depending on the model. Beside that, the Balkan Peninsula is under great influence of the Mediterranean Sea. These are some of the reasons why it is necessary to perform climate change impact studies using a Regional Climate Model (RCM) coupled with an ocean model. Such model has a larger resolution than a GCM, thus better resolves processes related to complex topography of the region, and it takes into account the important influence of the nearby sea. In this study we used the results obtained by the Coupled RCM EBU-POM (Eta Belgrade University - Princeton Ocean Model, Djurdjevic and Rajkovic, 2008). Climate projections are performed for a base period 1961-1990 (experiment 20c3m), representing the present climate, and for two periods in the future: 2001-2030 (scenario A1B) and 2071-2100 (scenario A1B and A2). Analyzing a period of thirty years is considered to be valid for climate studies because it is able to capture 75% of the variance of the true signal (Huntingford et al., 2003), as well as statistically significant changes in extreme Proc. XXVIII th IHC – IS Viti&Climate: Effect of Climate Change on Production and Quality of Grapevines and Their Products Eds.: B. Bravdo and H. Medrano Acta Hort. 931, ISHS 2012